FIG. 1 shows a conventional, pre-expanded cold shrinkable termination to be mounted on a high voltage electric power cable. The conventional cold shrinkable termination has an insulation body 1 having a terminating end and an opposite cable receiving end, a stress control tube 2, and a terminating end connection member 5. The terminating end connection member 5 is sealed on the terminating end of the insulation body 1 and electrically connected to a conductor core of the electric power cable. The stress control tube 2 is positioned on an inner wall of the insulation body 1 on the cable receiving end of the insulation body 1.
The electric power cable has a conductor core, an insulation layer covering the conductor core, a conductive shielding layer covering the insulation layer, and an outer sheath covering the conductive shielding layer. In order to terminate the electric power cable to other electric elements, a length of sheath must be firstly removed to expose a length of conductive shielding layer. A section of the exposed conductive shielding layer is then removed to expose a length of insulation layer. Lastly, a section of the exposed insulation layer is removed to expose a length of conductor core.
After a section of conductive shielding layer is removed from the electric power cable, it causes an electric field concentration on a region of the electric power cable on which the conductive shielding layer has been removed. Conventionally, as shown in FIG. 1, in order to decrease the electric field concentration on the region of the electric power cable, a stress control tube 2 is provided to cover the region of the electric power cable.
However, the stress control tube 2 only extends on the region of the electric power cable on which the conductive shielding layer has been removed, and does not extend onto and cover a part of the conductive shielding layer of the electric power cable that is not removed. Accordingly, as shown in FIG. 1, when the cold shrinkable termination is mounted on the electric power cable, if an end surface (left end surface shown in FIG. 1) of the stress control tube 2 is not abutted against an end surface (right end surface shown in FIG. 1) of the conductive shielding layer of the electric power cable that is not removed, there is a gap between the two end surfaces and a local electric field concentration occurs at the gap. Thereby, the conventional cold shrinkable termination is required to be mounted with high precision on the electric power cable. The need for the high level of precision makes it extremely difficult for an operator to accurately mount the cold shrinkable termination on the electric power cable.
Furthermore, as shown in FIG. 1, in order to seal the right end of the cold shrinkable termination (the right end of the clod shrinkable termination is upward in use, and is also referred as a top end), the terminating end connection member 5 is hermetically crimped on the right end of the cold shrinkable termination to prevent water or moisture from entering into the cold shrinkable termination.
European patent application No. EP0944944B1 also discloses a conventional cold shrinkable termination having a plurality of insulation material layers overlapped with each other and a stress control compound material lined within the cold shrink termination. The stress control compound material has a conformable dielectric constant to uniformly distribute the electric field. However, the stress control compound material generates a great amount of heat and causes a local high temperature in use; thus accelerating the aging of the stress control compound material and shortening the service life of the cold shrink termination.